Improvement in sewing-machines



UNITED STATES PATENT OFFICE.

D. B. PIPER, OF WINGHENDON, MASSACHUSETTS.

IMPROVEMENT IN SEWING-MACHINES.

Specification forming part of Letters Patent No. 56,990, dated August 7, 1866.

To all whom it may concern:

Be it known that l, DENNIs B. PIPER, of Winchendon, in the county of Worcester and State of Massachusetts, have invented a new and useful Improvement in Chain-Stitch Sewing-Machines; and I do hereby declare the same to be fully described in the following specification and represented in the accompanying drawings, of which Figure 1 is a longitudinal section of a sewing-machine provided with my invention. Fig. 2 is a side view, and Fig. 3 an edge view, of the mechanism constituting my invention, it being shown in vertical section in Fig. 1.

In such drawings, A denotes the looper, B the looper-shaft, O the cam-shaft, and D the needle.

The looper-shaft B is usually operated by a rigid or inelastic connection-bar extending from a crank fixed on such shaft to either cam or an eccentric fixed on the cam-shaft 0.

Instead of using an inelastic connection, as described, I employ an elastic one, which may be thus described It is composed of a yoke, D, a connection-rod, E, and a helical spring, F. The spring encompasses the rod, and is arranged between two shoulders or projections, a b, of the yoke. The rod slides freely through such parts a, b of the yoke, and has the upper end of the spring fastened to it, the lower end of the said spring resting on the lower projection, b. The pin 0 of the crank-wheel G of the looper-shaft goes through the lower part or head d of the rod E. The upper end of the rod abuts against the periphery of a cam, H, which is carried by the cam-shaft O. The yoke turns freely on and is suspended from the cam-shaft H, or from a cylindrical projection, 0, extending from the cam H, and being concentric with the cam-shaft. A setscrew, f, screwed into the said projection, serves to fix the projection and the cam to the shaft.

The purpose of the elastic connection is to prevent the loop from being drawn so tightly on the looper as to be broken. When a rigid or metallic connection is employed this accident is liable to occur. Besides this, the elastic connection, made as described, and with the rod E free to revolve in its supports a I), will easily accommodate itself to the two shafts whether they are inexact parallelism, or somewhat out of parallelism, or in one plane, as well as while they are in revolution.

The elastic connection enables the sewing- Inachine to be worked with very little tension on the thread, as the loop will be kept well drawn upon the looper. With the said elastic connection applied to the shaft 0, and the cam H made as represented, such cam being for the purpose of regulating the movements of the looper, there will be no danger of a V stitch being dropped while the machine is at work.

I make no claim to the inelastic connectionrod extending from the crank pin of the looper-shaft, and having either an eccentric or grooved cam for operating it, such eccentric or cam being fixed to the shaft which carries the cranked cam, whereby the feeding mechanism and the needle-bar are operated.

What I claim as my invention is The combination of the elastic connection, substantially as described, consisting of the yoke D, the rod E, and the spring F, or their equivalent, with the crank or crank-wheel G of the looper-shaft, and with the cam H, applied to the cam-shaft, as described.

DENNIS B. PIPER.

Witnesses R. H. EDDY, F. CURTIS. 

